I am a paying member of Translators'  base for 2011, but I will not renew my subscription in 2012 because it is expensive for the low job posting (only 5 per week in my language pairs) compared to Proz or Translators'Café (5 or 10 per day) and there are only end clients, no agencies, so I completed only 10 jobs in 2011 of clients of Translators'base and because all 10 jobs were CVs, I never received any more work from these clients because they do not need anything else to be translated, since they are not companies or translation agencies. So, it is not a scam as you said, but it is not interesting at all for translators.

Happy holidays!