Is this a case of geek trends being at odds with mainstream? Or is it that the mainstream hasn't yet caught onto the cool music sites? Let's check out and analyze the stats from both comScore and our poll....

Note that last.fm isn't categorized as 'Internet Radio' by comScore and as far as we know, it isn't part of CBS Radio listed above. We asked CBS (which owns last.fm) to send us the comScore data they have on last.fm, and here it is for the same period:

Notable Trends

AOL Music, with 23.9 million unique visitors in July 08, is the strongest. It recorded a 56% increase over the past year, so its growth is very good. Yahoo Music is second with 18.7M uniques in July 08, however it has decreased 19% annually since July 07. Clear Channel Online, the largest operator of radio stations (amongst other things) in the US, is a clear third with 9.4M audience in July 08.

As for the online streaming sites that began as startups, despite its continuing legal woes and the fact it can't be heard throughout much of the rest of the world, Pandora's US growth has been very impressive: an 89% increase from last year, to 4.8M unique visitors in July. Its competitor last.fm had just over 3M unique visitors in July 08, and 62% annual growth.

We also checked Compete and their stats are fairly similar, in terms of the trends, to comScore's. Compete has Pandora at 81.8% annual growth, with last.fm at 72.6%:

So the overall trend here is that both Pandora and last.fm are showing strong growth. But AOL Music continues to set the pace. Yahoo Music must be worried about its decline.

ReadWriteWeb Poll: last.fm and Pandora Still Most Popular

Our poll asked: what are your favorite online music streaming services? We ran almost the same poll last year. The results have shown that there is more diversity this year in the number of online music services that our readers tune into. While Last.fm and Pandora once again came out a clear first and second (respectively), other apps made a strong showing. Last.fm got 19% and Pandora 15%. Last year last.fm was at 31% and Pandora 29%, although last year's poll wasn't multi-choice.

Of the smaller services, Highnote, lala.com, Seeqpod all polled at the 8-9% range this year. Non-radio services such as Imeem and iTunes Music Service drew around 4-5%, while small but trendy services Hype Machine and Muxtape both came in at 4%.

So last.fm and Pandora are still favorites among the early adopter and tech-savvy people that read our site. But it's great to see so much interest in the many new online music startups (some of whom we didn't manage to fit into our poll, it must be said). As a matter of interest, here are some Compete stats for a few of the well performing smaller sites in our poll:

Hype Machine is perhaps the one to watch here, with 177% growth annually and on an upward trend. It grew 10.2% last month alone.

Conclusion

So AOL and Yahoo still dominate music streaming in the US, but last.fm and Pandora are beloved by many of our readers, and are growing fast in comScore too. We asked our panelists in our podcast show this week (link below) which sites they think will be popular this time next year. We'd like to ask the same question here. Do you see any dark horses amongst the smaller services, that may even show up in next year's comScore charts?

See also: Future of Online Music - Industry Players Discuss. This presents highlights from our podcast show earlier this week, in which senior representatives from Yahoo Music, Imeem and Rhapsody discussed online music trends.