I've dabbled a little in Haskel so I'm vaguely familiar with the concept of monads. Monads are a way to maintain state in functional languages. Perl is hardly functional, although with some contortions, it can be used in a functional manner. So why monads in Perl? It already has many ways to produce side effects. I guess the main reason is that it can be done and this article
shows how to do it.
has been getting a bit of buzz lately. It's the new open source search engine project headed bu Wikipedia founder, Jimmy Wales. A good open source search engine is really needed. We're all too reliant on Google. The problem with Google is that it's algorithms are hidden and thus subject to manipulation by Google, for example, to meet the approval
of various governments such as China's. The down side to an open source search engine seems to be that it will be easier for web sites to manipulate their page positions than the hidden and changing Google algorithms. Since you can know how the engine is indexing, it seems that you could adjust your site to get a high page index. Wales has indicated that Wikia Search, a for-profit company, will allow anyone to build a search engine. That would be interesting - If we each had our own engine, tailored to our own wants and needs. Certainly, that would be great for individual web sites, but I think it may be a while before anyone can seriously challenge Google as a general purpose web search engine.
Here is a list of Open Source search tools. http://www.searchtools.com/tools/tools-opensource.html