In my recent podcast with Robert Scoble, one of the issues I raised with him was how much easier text blogs are to index for a search engine, than are podcasts or videoblogs. Robert agreed that this was the case but he made the point that search engines are using link text and the text surrounding the links to podcasts and videoblogs as a means to indexing their content – not ideal but it’s a start.

Robert went on to predict that because technologies are currently being developed to allow for the indexing of these mediacasts that we will see great strides in this area in the next twelve months.

Sure enough today I found a comparative review on Yahoo! News of three podcast search engines which use speech-to-text software to generate written transcripts of the podcasts. The three reviewed are Podzinger, Podscope and Blinkx.

I searched the three sites for the term “Scoble” – Podscope found no podcasts with that term (!), Podzinger found 5, and Blinkx found about 50. I say around 50 for Blinkx because its horrific interface actually made it quite difficult to see how many results there were! None found the podcast I did with Robert Scoble last week!

All three include the ability to add your podcast to the index but the Blinkx link ended in a 404 for me!

However, things are set to improve – as the Yahoo! report put it:

the engines can learn better ways to determine words from their context.

Blinkx co-founder Suranga Chandratillake illustrates the process this way: If a podcast were made about the topics in this story, a computer probably would be right if it detected the phrase “recognize speech.”

But in a podcast about last year’s tsunami, the computer would do better to hear almost the same sounds as “wreck a nice beach.”