HI if the site was on the top ten of google search results for the chosen KW, you could expect a good deal of traffic. Traffic = money for sure.
are they new domains? or established domains that where getting that sort of traffic?
if new?
you could use simple math to work out what is the best /easiest domain to choose.
say you choose a word with 20K searches a month, then divide that by how many competing websites. say 1mil. ratio 1mil/20K = 50-1
then another that only get 15K Per month but only 300K competing sites = 20-1 ratio or 2.5 times easier.... it dosent mean you will rank for anything, only it make it easier and the likely hood far greater,.
Some domains dont need a lot of traffic either. my best by miles $200 a month every month only gets -/+1000 visits or so, you do need some traffic though or the wheels fall off.
if you want to rank for your keywords. the only advice i can give is make sure your domain name KW's is in your title in the same order and again say in the footer. and dont over do it (spammy)
then whatever keyword you want to be found for. say "blolisticed" have your domain hyperlink somewhere near it, or in the tag itself ie:
www.blolisticed.com
try forums that have /follow. and have a bit of pagerank to get indexed fast.
and hey presto.. SERP love