Evoking imagery of conjuring something unseen from a digital hat, this magical card links thematically with Ele "Smoke" Scovak: Cynosure of the Net. It also has some interesting thematic and mechanical interactions with several other cards.
Of course, this card pairs nicely with anything that gives you information about the cards in R&D. See the top card using Woman in the Red Dress, Spy Camera, or Globalsec Security Clearance then bypass it if you want to keep digging. Do this as many times as you can run R&D in a turn for an additional unique access each time (barring additional shenanigans).
As the number of successful R&D runs increases, there are other interesting interactions.
With Equivocation the interaction is relevant on your first successful run on R&D. If you don't want to access the card revealed by Equivocation (it's not an agenda or must trash asset for example) you have options. One is to put that card in the corps hand, allowing you to access the second card directly. Another is to not put that in the corps hand, and use Top Hat to access the second card. Or third or fourth or fifth but without additional information these are functionally equivalent. Why choose one over the other? Well obviously on the one hand you are denying the corp a free draw by using Top Hat, usually to be preferred although mill type decks or certain combos may choose to offer the card anyway. As has been noted, in using Top Hat you forgo accessing any cards in the root, allowing you to dodge cards like Prisec, Cyberdex Virus Suite, Mumbad Virtual Tour, Disposable HQ, or Product Placement. That can be good. At the same time, you may want to access and trash any number of upgrades (Caprice Nisei or that Crisium Grid that's blocking your Indexing play, the list goes on) and therefore you may choose not to activate Top Hat.
So, impressive tactical flexibility in this combo that gets you: one access you want or reveals two cards with one blind access and potentially dodges an ambush or mills corp. All for the net price of 0. That compares favourably with the tempo hit of of 4 for R&D Interface. However you are also dedicating 1, which can be tight in stealth decks like Smoke
Now, on the second run things get more interesting. Obviously, your second run can dig past uninteresting reveals from a Find the Truth run elsewhere. Or, you can run R&D with Find the Truth on your first run, either accessing the reveled card or bypassing it as with Equivocation above.
Indexing presents perhaps the most interesting multi-run interactions. Find but can't access 2 agendas? Bury 1 deep and potentially grab it next turn. Or, continue to get unique accesses on subsequent turns while you maintain R&D lock for up to 5 turns.
Obviously, Top Hat will pair will with cards that reward multiple runs. Temüjin Contract, Net Mercur, The Turning Wheel (to gain tokens - you can't combine them), Datasucker. Consoles like Doppelgänger or Mirror. Events like Dirty Laundry or Möbius.
Other interactions (of admittedly limited utility):
Dodge the operation that Seidr Laboratories: Destiny Defined pulls from Archives when you their ICE.
As R&D dwindles, do deep digs against decks that have been using Daily Business Show, Sensie Actors Union, or Shannon Claire
It's not unique. Get consistency and credits by running 3 and feeding additional copies to Aesop's Pawnshop. Great value if you installed it for 0 using Hayley Kaplan: Universal Scholar
Bottom line - is this a tier one tournament card? Not as of this writing and maybe never (Station One). Is it interesting and playable? Yes.