TEX.SX is a source of knowledge such as online encyclopedia (i.e. WP) but experts focus on (question/answer model). The issue facing online encyclopedia is how to get one source of knowledge available for a wide audience.
AFAIK, the only way to have access to old posts in TEX.SX is to use the search engine. This tool is powerful, with advanced options, but it is not sufficient. Indeed, people use to consult only the 5-10 first results (like in google). Lots of questions are not very accessible (because the asker does not use the correct tag/keywords, because the title of the question is formulated in such way it is not easy to find it, ...). I preferred sometimes to have a list of question by subjects (like in some faq). For example :
Biblatex- creating your own style
- question 1
- question 2
- question 3
- creating your own style
In parallel to the search engine, is there a repository of questions by tag/themes? Should we create one (perhaps with only popular/well noted questions ?
TAG-power like big-list, tutorials and faq which does not need even tags. Wiki-type-knowledge-bank-of-TeX.SX: Often referenced questions and Collecting FAQ on LaTeX in this site into a recipe book that is collaberatively developed by us:)