It's obviously not a formal distinction. Algorithmic means "spends a lot of time running loops doing something interesting" as opposed to "copies data back and forth between the UI and the DB". Or CPU intensive versus IO intensive.

[Edit] And just to be completely clear and also reap all the downvotes that I can get from disgruntled web devs: Python and Ruby are indeed totally unsuitable for writing CPU intensive, complex algorithms. If you write Ruby or Python code, avoid loops! Try to be declarative so all the loops stay in the C code.