On my recent trip to Seattle, I visited the offices of iLike in the Capitol Hill section of that lovely Pacific Northwest city to take a video gander at one of the more interesting start ups to emerge from the social-networking arena.

The music discovery site, unlike a lot of others in its sector, has been plugging away for several years with much less funding–about $16 million from the founding Partovi twin brothers, former AOL (TWX) wunderkind Bob Pittman and a big slug from Ticketmaster (IAC)–but with a lot more impact.

Like its competitors, such as Last.fm, it has forged its popularity by focusing on linking its users with one other and musical artists via what they like to listen to.

Kind of like that old shampoo cliché: She told two friends and she told two friends and so on and so on and so on.

It’s actually quite an infectious app and also Web site, with 30 million registered users, and it’s one of the few that is useful on social-networking sites like Facebook, hi5, Orkut and Bebo.

So useful, in fact, that Facebook has selected the service as one of only two “preferred” partners, a designation Facebook announced today at its second developers conference in San Francisco.

iLike was the brainchild of Ali and Hadi Partovi, longtime Web entrepreneurs who have also worked at big companies like Microsoft (MSFT), and whose interest in music and online delivery was the inspiration for the site.

To make money, iLike has a number of businesses.

First and foremost it is essentially a lead-generator for sites like Amazon (AMZN), iTunes, Ticketmaster, and more recently, the Rhapsody subscription music service, with which it just added a somewhat restricted full-song playback offering.

And iLike has just launched an ad platform for concert promoters.

The brand itself, although focused on music right now, obviously has extension possibilities (iLike movies? iLike TV? iLike tacky theme parks?).

Most observers of iLike assume it will sell to a larger entity eventually, such as Ticketmaster, for whom the site has become a major referrer.

But the Partovis–who have sold start ups before–insist they want to build the iLike brand.

Here’s a video interview with Hadi Partovi in which we talk about all this and more, along with a tour of iLike’s offices:

Gifts.com President & CEO William Lynch, who founded the site for IAC (IACI), will transition to HSN full-time as its EVP of marketing and content. He had previously been managing the HSN.com site, while also running Gifts.com.

The site, which also offers gift cards that can be redeemed at over 100 merchants, is now a 40-person operation.

Rapp has been with IAC since 2006 and, prior to joining the company, worked at the New York Times Company.

After a contentious battle with large shareholder Liberty Media, IAC is in the midst of separating itself into five publicly traded companies, expected to be completed in the third quarter, spinning off HSN, Ticketmaster, Interval International and LendingTree.

Left in the new IAC will be: Ask.com, Bloglines, Citysearch, CursorMania, Evite, Excite, IAC Advertising Solutions, InsiderPages, iWon, My Fun Cards, My Way, Popular Screensavers, Smiley Central, Vimeo, Webfetti and Zwinky, Match.com, ServiceMagic, Shoebuy.com, Entertainment Publications, ReserveAmerica; Pronto, Gifts.com, Green.com, Primal Ventures, InstantAction, BustedTees, CollegeHumor, GarageGames, RushmoreDrive.com, Very Short List, and 23/6.

Also included will IAC’s current investments in Active.com, Brightcove, FiLife, MerchantCircle, OpenTable, Points.com and SHOP Channel.

“I am beginning to think these people are insane. … Everything they cite is hogwash.”

That’s what is known as a classic Barry Diller, who can be relied on to come out with a good one when provoked.

In this case, the provocateur is Liberty Media’s John Malone (pictured on the right in this comic with Diller), whose company has headed to court to try to remove Diller from his job as chairman and CEO of IAC/InterActiveCorp.

As chronicled by the always deft Jessica Vascellaro of The Wall Street Journal today, the fight between the longtime partners is getting uglier still with–oh, let’s just admit it–totally confusing moves and countermoves about the fate of IAC and its subsidiaries.

Liberty has a giant stake in all of these entities and Diller, of course, has control of that stake. A recipe for mogul mud wrestling, if ever there was one.

But the fight is a serious one for a number of high-profile Web companies within IAC, which was being restructured to stop just this kind of fighting between Diller and Malone.

Just how Diller has gone about rejiggering it all, in complicated spin-offs in a way that allegedly undercuts Liberty’s control yet again, is what set the new round of tensions off.

Those sites embroiled in the fighting include: Expedia, TicketMaster, LendingTree and Ask.

As luck would have it, Diller will be interviewed onstage at the sixth edition of D: All Things Digital in late May, so there will be plenty to talk about!

The last time I interviewed him at the Monaco Media Forum last November, Diller let loose too, when he memorably scoffed at the $15 billion valuation for Facebook and Microsoft’s $240 million investment in the hot social network.

“If it was real money, it would be insane, but since it isn’t really, then why bother [worrying about it],” said Diller. “It doesn’t mean anything, it is a phantom, false valuation. Let them sell for $14 billion, $998 million, and then I’ll believe them.”