How do hostels in the US compare with hostels in Europe? Are they similar in terms of convenience, availability, cost, amenities, etc? Or is the "hostel culture" completely different in the two places?
It occurs to me that I've only ever stayed in one hostel in the US, and it was a 17 bed dorm of hell with a Russian snoring in it. Which is pretty much like every other hostel around the world ;)
To be fair, I've been in a lot of hostels, some are good, some are bad, but for the most part they follow a similar pattern - dorms with bunks and a basic breakfast sometimes. Good ones have a common room, helpful staff, wifi and a happy vibe. Bad ones have cockroaches, randy people in the bunk above you, little personal space and no security, and are staffed by an old goat with a beergut.
The rest of the 'differences' are simply what makes them unique, and the experiences you have at them make for stories - good or bad. :)
But given that hostelworld and hostelbookers both use the same criteria for hostels in the US and in Europe (and anywhere else for that matter), and I've never heard anyone say anything weird about them being 'different', I'd say if you were happy in one, you're likely to be happy in a similar standard one in the other.
(and I've had a lot of Americans stay at hostels I've been at, and never heard any of them say 'This is nothing like hostels back home!')
Update, I stayed in a hostel in Honolulu in April, and another in Seattle in May. Just like any other hostel, I assure you :)
In Europe the term "Hostel" is not so common anymore. Hostel has the connotation of being a cheap and uncomfortable form of budget accomodation. The snoring roommate maybe being the main caricature. In the Netherlands for example, the youth-hostel chain changed its name to stayokay.
It might be worthwhile to compile a list of synonyms for budget-accommodation forms in the country you intent to visit. Bed & breakfast works in many countries, but sometimes you can find really nice accommodation if you search for local alternatives in the same price range as a hostel. chambre d'hotes (France), Zimmer frei (Netherlands), Gastenkamer (Belgium), Agriturismu (Italy).
Biggest difference are IMHO the people who visit those hostels. In Europe you get the Americans, Australians and south-Americans, and in America you get the Europeans, Australians and yes, more Americans. I always found it odd if people hostel in their own country, but in American hostels that seems to be quite normal.
The other difference i noticed was that the American hostels where mostly run-down ex hotels with dirty carpets and smelling couches, while the hotels in Europe seemed to be cleaner in general.
I agree with Mark and thiton that the differences between individual hostels are vaster than the difference between US and European style of hostels generally.
But there is one kind of hostel common in some parts of Europe that I haven't encountered in the US.
Especially in Germany but also nearby including at least Austria and Luxembourg I have encountered a style of large old "institutional" hostels run by Hostelling International (HI).
The "hostelling movement" started in Germany and these seem to have sprung up from that original movement and many of them are still going. They seem to cater either to large groups of children or groups of families. Typically they are very large and well outside the centres of cities. You won't have much of a relationship with the staff who are much more like mere employees than cool travellers to hang out with that you might find in small hostels. They also typically have large canteen-style dinging rooms and the breakfasts can be pretty good. Some seem to offer other meals besides breakfast also.
The prices can vary wildly. Back in 2001 I found some of these hostels to be amongst the cheapest, while others were so expensive I couldn't afford to stay. Also back then at least in Bavaria these hostels strictly enforced an upper age limit for guests of 26 years.
The first European hostel I ever stayed in was one of these in Frankfurt am Main, Germany ten years ago, Haus der Jugend. Most recently I stayed at one on the edge of Vienna last year, Hostel Hütteldorf.
The hostel culture in Europe already differs so widely that any significant difference with the US is unlikely.
Many of the HI hostels in Europe are new buildings with two-bed and some four-bed rooms, much closer to hotels than hostels in anything but name. On the other hand, the large tourist cities feature many dirty, snoring-heavy 20-bed dorms. And there are plenty of small, almost family-style and very nice hostels in the cities of central and eastern Europe.