Why doesn't all of the fiverr clones get sued? I did a quick search and fiverr has a few trademarks that many micro online websites are definitely infringing on, so why do they continue to exist and popup? Also, it's kind of hard to search for patents but isn't it safe to assume that the script for fiverr is patented, or can that not be patented?
The holder of a trademark has an affirmative duty to police its trademark. However, that does not mean they have to go to extraordinary lengths to do so. These fiverr clones may have received cease and desist letters and ignored them; and fiverr may not be able to find them to take them down. The script could be patented, but I wouldn't assume it has been.