"Paid.co" is a high end domain name designed for a fin-tech product or startup.
The name "paid" has only four characters and just one syllable. Mono-syllable names are very rare and highly valued. Established brands using one syllable names include Nike, Ford and Shell.
This domain was first registered in July 2010. Older domains have an advantage when ranking in search engines.
Paid.co is a dot co domain. Dot co domains were introduced to keep up with demand for short, global domain names. This domain extension has become increasingly popular among tech start-ups, including Twitter (t.co).