Brainteki has it right. But since it has been 5 years, let's revisit this a bit.
Project Junebug is the trap to which all other trap are compared. At one influence, it can be used in any deck where you need a good trap.
A big advantage of Project Junebug is that, when you'll use it, which is usually Install-Advance-Advance, it look just like a NGO Front or a future 3 points agenda. The runner has to choose to take the risk of : 1-making a run for nothing, 2-making a run and losing 4 cards, possibly getting flatline, 3-no making the run and letting the corp score a 3 points agenda, 4-making the run an scoring the agenda (but not in this case). When the corp is on game point, it is a really tough choice.
On top of this, this trap (like Cerebral Overwriter and Aggressive Secretary) can be used with Mushin No Shin to great effect. Using a Mushin No Shin on this give the runner an even tougher choice. 6 cards is a lot. 3 points is a lot.
But what if the runner does not run and then you have an advanced trap sitting on the board for nothing? Enter the other one influence card : Back Channel. This will let you "score" Project Junebug tokens for 3 credits per token. Advance Project Junebug to 5 or 6 tokens and the runner will start to think it might be a False Flag (3 agenda points for 7 advances, 1 tag per 2 advance). If the runner run it, this can deal 10 or 12 net damage, insuring a flatline. Otherwise, this could net you 12 creds in 2 turns, or even more if you used Mushin No Shin. Pretty neat.
Using Back Channel, Project Junebug can also be combined with La Costa Grid, to let it self advance to get those sweet 3 credits without even paying for advance or using clicks (don't push it too far, the runner will find other ways).
Finally, you can combine Project Junebug with Upgrade traps, like Hokusai Grid and Prisec, to get an even greater effect.
Of course, there are cards to protect the runner : No One Home. On The Lam, The Noble Path, Recon Drone, Ramujan, Heartbeat, Deus X, Caldera, Guru Davinder, Sacrificial Clone, Bio-Modeled Network. The problem of those card is always the same, it target corp that does damage. So they can also be dead cards.
Comparable to Project Junebug (in faction) are Snare!, Psychic Field, Shi.Kyu and Gene Splicer. Snare trigger from R&D. Shi.Kyu trigger also from Archive (but not R&D), Psychic Field will take ALL the card of the runner, but not flatline. And Gene Splicer does half the damage but will grant an agenda point (often the 7th agenda point).
If you want to play the shell and bluff game, Project Junebug is damn good. Shell game is its own kind of thing in Netrunner. A special kind of fun, where you dare the runner to make runs.