The nice thing about economy cards like this one is that it should be possible to objectively work out how they compare to other economy cards you might be using. So here's my take on this one.

Friend of a Friend is clearly intended to be used alongside Sebastião Souza Pessoa: Activist Organizer, or "Seb" as the chat on jinteki.net has taken to calling him. So I'm going to do the math primarily on the basis that you have Seb on your side, either as your identity or via DJ Fenris. The basic problem with doing Seb math is that the economy comes in two halves: first you tag yourself, and then you untag yourself, to end up with some net gain; but the problem is that the tagging and untagging cards are usually different, so in order to work out how good a card is economically, you need to somehow split up the gain between the two cards and decide which one is responsible.

However, there's a reasonably convincing way to work this out. If you have an untagger but not a tagger, the untagger is losing a lot of value and is mostly useless (e.g. if you play Friend of a Friend and then use its untag ability whilst not actually tagged, you have spent , , 3 to gain 5, i.e. two clicks to gain two credits, and might as well have just clicked for credits instead) – as such, we can assume that the untaggers are useless except when tagged. If you have a tagger but not an untagger, then assuming you don't want to float the tag (because 1. it is dangerous and 2. doing that turns off most of Seb's support cards), you will have to remove the tag manually, spending , 2 to use the basic action. So the obvious way to work out the value of the untagging card is to see how much more it gains than the basic untagging action – any gain above that must be coming from the tagging card instead. Let's see how this reasoning applies to Friend of a Friend's two abilities.

The untag ability

First, let's look at the untag ability. Taking the , 3 it takes to install this card into account, using this ability means that we have spent , , 3 to gain , 2, 5 (i.e. an untag and 5 credits). That's a net trade of the card and a click for 4 credits, an economic trade that most Netrunner players are very familiar with – it's a Sure Gamble! In other words, if you play this card planning to use its first ability, you are in effect saying "I am going to temporarily go down 3, but the next time I would remove a tag, my 3 will get refunded and I will get the gain of a Sure Gamble on top of that".

How valuable is this? Well, a Sure Gamble is incredibly valuable (arguably the best economic card in the game that hasn't been banned). Going down on credits temporarily in order to get a Sure Gamble worth of value is also pretty common (if you're rich enough, the delay in gaining the credits usually ends up not mattering); Daily Casts gives one more credit but on a 4-turn delay, and while the delay means it isn't quite as good as Sure Gamble, it's still considered a staple that is run in a wide range of Runner decks. So for the untag ability to be good, basically all that is required is that your deck won't go too long without needing to remove a tag.

One caveat with this ability is that it can compete with other untagging abilities. For example, if you are using Networking as your primary way to remove tags, rather than the basic action, then the cost of a tag needs to be evaluated at , 1 rather than , 2 – that makes this ability into an Easy Mark rather than a Sure Gamble, which generally isn't worth it.

The tag ability

What about the ability to tag yourself? Well, if you don't have a way to get positive side effects from the tag, it's pretty terrible: counting the cost to untag, you're spending the card and , , , 3, 2 to gain 9, i.e. 3 clicks and a card for 4 credits, which is actually a loss rather than a gain (both cards and clicks are more valuable than credits). This is why Friend of a Friend is clearly intended to be a Seb card: Seb will trigger when the tag is gained, and that trigger provides additional value.

We can calculate the value of a Seb trigger the same way we calculated the value of an untag, by seeing how much better it is than the equivalent basic action. In this case, installing a card from grip usually costs , and Seb provides a 2 discount on the install – so as long as you have an appropriate connection in hand, the value of the Seb trigger is , 2. This happens to be the same as the value of a basic-action untag, so effectively, what's happening here is that when you have Seb's ability available, taking your first tag doesn't matter at all; the resources you would spend on installing the connection are the same as the resources you would spend on removing the tag.

This means that in the scenario where we have Seb, along with a connection that costs at least 2 and that we actually want to install, the effective trade made by the second ability is to trade the card and , , 3 for 9. Again, this is a recognisable card, Lucky Find. It's hard to gather data on just how good Lucky Find is as an economic card; it isn't widely played, most likely due to its influence cost (2 universal influence is a lot for an economy card), and thus it's hard to get an idea of just how valuable a Lucky Find is. I think most methods of counting it put it approximately on the level of Sure Gamble, though.

As a sanity check, we can compare two Friends of a Friend to the Sure Gamble + Lucky Find combination:

• If you play Sure Gamble and Lucky Find and manually install a 2 connection, you have spent ++ and 5+3+2 to gain a total of 9+9 and an install. This is a net trade of and the 2 event cards to gain 8 and an install.
• If you play two Friends of a Friend, using one to tag yourself and one to untag yourself, and installing a 2 connection with the resulting Seb trigger, you have spent +++ and 3+3 to gain 5+9 and an install. Again, this is a net trade of and the 2 resource cards to gain 8 and an install.

This produces the expected result, that the gains are equal, which has made me reasonably confident that the calculations are correct.

Comparison and conclusions

There's a nice symmetry between the two abilities on Friend of a Friend. The untag is very comparable to Sure Gamble (but useful only if you need an untag), but gets worse if you have alternative untagging methods. The tag ability is very comparable to Lucky Find (but useful only if you have Seb and a connection that you want to install), and gets better if you have alternative untagging methods (because then you get to clear the tag more cheaply). This means that which ability you end up using will depend primarily on what else is in your deck. Conceptually, using the tag ability is "better" than using the untag ability – they start out comparable even when untagging with the basic action, but the tag ability gets better as your deck gains more methods of cheaply untagging. However, Seb decks often have lots of other sources of tags, and to get value from the Seb triggers, each tag needs to be paired with a connection to install (and duplicates are useful only if the connection is useful in duplicates) – in practice, it's fairly common to not have enough usefully installable connections to make the tag ability worth it (even in decks that are running 20+ connections). As such, this card normally seems to be used for the untag rather than the tag in practice (although because you don't have to choose which ability to use until you actually use it, if you do end up with a glut of connections you would like to install, then it's definitely correct to use the tagging side of this card to help you get value from installing them). It's not like there's a "right" or "wrong" side of the card – it's more that the correct side varies with the circumstances, and either will give you similar amounts of value when the appropriate situation comes up, but one situation is more likely to come up than the other.

There is one other reason to run this card in Seb – although the fact hasn't been mentioned so far this review, Friend of a Friend is itself a connection that costs at least 2. One real problem with Seb decks is getting enough installable connections to be able to keep getting value from the Seb triggers (and in turn, effectively removing the downside from your abilities that tag yourself). Something of a threat to that style of deck is that either you don't play enough connections to make the tagging abilities usable, or else you have to resort to mediocre connections like Scrubber, that probably wouldn't be in your deck otherwise, in order to give the ability something to install (and doing that makes all your tagging cards worse because the Seb trigger is no longer providing its full value). If your deck is trying to take substantial advantage of Seb triggers, then Friend of a Friend should be very strongly considered as a 3-of because it goes into an "economy slot" but, unlike the economic cards you would likely be using instead, also helps increase your density of usefully installable connections and thus reduces the chance that you might end up gaining a tag whilst having nothing to install with it.

What if you aren't using Seb? In that case, the tag ability is basically worthless, and the untag ability useful only if 1. you got enough value when self-inflicting a tag to compensate even without the Seb trigger, or 2. you were tagged unwillingly/unexpectedly and now need to clear it. The former situation would be weird (although it could happen if you were running Thunder Art Gallery and Rogue Trading in a non-Seb deck). The latter situation probably depends on what the Corp is doing, and thus it would mean this would be a tech card – but you don't generally want your tech card against tags to clear exactly one tag, because you generally get tagged more than that in a game, and dedicating many slots to cards that aren't useful in all matchups is typically a losing strategy.

So the overall conclusion: if you aren't using a strategy based around tagging yourself for a benefit and then clearing the tags, this card isn't appropriate for your deck. However, if you're using Seb, it's pretty much an auto-include; depending on which half of your deck you're drawing, it will fill in the other half as either a Sure Gamble or Lucky Find, whilst also providing a usefully installable connection to help make sure that the Seb triggers aren't wasted. I would strongly suggest including three even if you're using Seb out of faction (via DJ Fenris) – it's only one dot of influence each, and a card that solves this many problems for the deck is probably going to be better than the economy event or resource you would have included instead.