The Tech Industry’s Darkest Secret: It’s All About Age (linkedin.com)

"The older worker likely has a family and needs to leave the office by 6 p.m. The young can easily pull all-nighters."

I come under young as I am 25 :) .. most of the +40 people I saw are in manager positions or they go towards architect level jobs

I believe the key here is not age, but skills. The author's quote "The young understand new technologies better than the old do" can be true, but not always. A developer who has learned perhaps 3 or 4 languages over the course of their career is much better suited to learning something new than a recent graduate with only classroom studies.

A bigger reason for perceived ageism is when technologists do not pay attention to their skills becoming dated. I see this quite a bit today with small companies more likely to use Python, functional languages, or Ruby than say Java or C#. For candidates that have been in large Java or .Net shops for 10-15 years, what they will view as ageism is likely something else. I wrote a blog about this just recently http://jobtipsforgeeks.com/2013/03/07/enterprisey/

The tech industry itself is mostly young. Of course, there were developers 20 years ago, but the big increase in number of people working in tech was as of the mid 90s. So there aren't that many people aged 45+ working in the tech industry today, simply because the industry is young. This will change in the coming 10 years, and I believe that smart developers who manage to keep their skills sharp and up to date will still have plenty to offer and will be in good shape in the job market.