[shadylane]

I can confirm this. Got a site with very low traffic and one with 138K sessions a month. These russian spam referral sites are all over the low traffic site but they barely appear on the high traffic one. Not sure why Google hasn't blocked these yet. The same domains (ilovevitaly.com, darodar.com, pricer.com etc.) have been referral spamming since at least mid December. In fact the range of domains doing this was so limited it was relatively easy to set up exclusion rules in GA. The only annoying thing is that the exclusions aren't retroactive.

[shadylane]

Actually, was referring to small, desperate sites rather than the SEO motivation. Being spam, makes sense to target less popular sites. I'm not going to investigate every referrer on a busy site, but if I've only got a dozen referrers then I might check out one site sending me 50 visits.