It's been a long time since I heard the term, probably late 90's or somewhere in that timeframe. At the time I was in the banking business and there were various services that were launching with the idea of aggregating bank accounts, rolling up loan offers into portals, etc. The term "disintermediation" was used as a label for what happened to you if you let someone else capture your customer's attention and just treat you like a supplier. I'm sure there were other uses at the time, and later.

"The term "disintermediation" was used as a label for what happened to you if you let someone else capture your customer's attention and just treat you like a supplier."

Banks, along with selling their own products, act as middlemen to sell other types of product (e.g. insurance). The only disintermediation I can think of in relation to retail banks, is the move for people to buy things like insurance from (i) web sites, who may kick back some of the commission that would otherwise go to the bank, or (ii) insurers who sell direct through their own channels.

What you describe is intermediation or reintermediation: http://www.investopedia.com/terms/r/reintermediation.asp