Proprietary software is the description given when an online bingo site uses its own uniquely designed software, and does not “buy-in” software from the giant software designers such as Dragonfish or Virtue Fusion. As such they are considered “independent”, rather like “indie” music companies are considered different from the multi-national conglomerates like Sony and Universal which control much of the industry.
The advantage of using such software is that being uniquely designed, you may well find these sites are a little different from the mainstream. So if you are an experienced player who is getting a little frustrated by the sameness of all those countless Dragonfish styled sites, one of the independently fashioned offerings may be worth a try. Examples of these proprietary sites are Bingo Cams (which offers players the opportunity to interact via webcam), GameVillage and Tombola Bingo. Some other sites use proprietary software as part of a portfolio of software designers: they are not fully independent, but do offer some uniquely designed features. Examples of these are BGO Bingo and Paddy Power Bingo.