One thing not mentioned in the other (excellent) reviews below: firing EBC triggers an R&D reshuffle, so it can protect you against Indexing: let them Index, then when they run R&D again to pick up the agenda, fire EBC to reshuffle it away again. Saved my bacon a couple of times!

Although trashing multiple programmes could well be devastating, actually pulling it off with Information Overload on its own is difficult. Firstly, you need the runner to be floating tags - multiple tags, ideally, since the Runner gets to decide what gets trashed - so before you rez, you'll need to have drawn the runner over tagging ice like Draven, Gutenberg, or Bandwidth. Giving a tag with Information Overload itself will be very expensive, what with the 6 rez cost and a base trace strength of only one. Finally, a 4-strength sentry dies so hard to Net-Ready Mimic it's not even funny.

The only way I can see to make Information Overload useful is with a big nasty Midseasons. (Or I suppose with multiple City Surveillances firing over a couple of turns, a la NEARPADs). Get the runner floating 7, 8, 9 tags and all of a sudden IO is very scary indeed.

assuming you ever get one of these to hit it'll be devastating (and as a tip, corporate troubleshooter is an excellent way to make it hit), but even if you can't, getting one rezzed against a heavily tagged runner is an amazing tax. Even net-ready mimic or 4tman will struggle to plow through this repeatedly with 6+ tags. —
The on-encounter ability can be taxing if you have any sort of trace-boosting stuff on the table. Many players are relying on resource-based economies right now, and they do not want to be tagged. This card has its place, but only in decks built to do a lot of tagging and/or capitalize on targets once the tagging occurs. —
Had this fire off at a tournament playing a Butchershop NEH. Runner stole an agenda and I mideseasons him with 14 tags and enough money to still spare. Managed rez this and cleared his whole board (including a few Plastcretes he had installed) and then scorched him. Requires some work to make it work, but when it works it does wonders. Still can die to Switchblade easily if the runner is playing a Stealth build with it. —
Unfortunately the on-encounter ability loses out to Data Raven. You've really got to be tagstorm to make this ICE worth it, I think. —