Many of the search tools recognise this and are smart enough to work out likely variations - but software isn't foolproof. Another example is closer to home. Most people know me as Bill Bennett - but Bill is a contraction of William. It's not an unusual practice to use a shortened version, but the move from William to Bill changes the first letter. While many Anglo-Irish people know this, it confuses others enormously.
Few computers are able to recognise the two names are the same.
One of the more frustrating aspects of searching for people online is that many of the search services are US-based. You can quite easily waste a lot of time hunting for an Australian, New Zealander or European only to discover that the search tool doesn't include people from these countries. In practice, people from outside North America are generally under-represented in online search databases. This actually represents a step backwards. In the early on-line era, most people finder tools were global.