I didn't write very clearly and I think you missed the point... Your prospective clients don't care about technology, they want to know how you are going to help them.
If you are a web agency, then you main page needs to focus upon meeting the desires of your expected clients. Here is the page for one of my local web agencies: http://www.hairylemon.co.nz/ . Hairy Lemon use open source when appropriate but they don't advertise it.
Read the article and substitute the word "opensource" wherever you see Wordpress... Think about that... Read the article every 1st of the month :-)
My point about RoR is that the company that created it (in all its open source glory) does not mention it on their own main web page - because their propective clients don't care about it.
PS: I am a tech head and love open source!
