One of the most useful accessories that you can provide in your blog, to make it visitor friendly, is a search gadget.
A search gadget lets a new visitor, just arrived at your blog from a search engine hit list, find more articles that may interest them. Besides a search gadget, which lets people search your blog on their terms, you may include one or more label searches, which lets people search your blog on your terms.
Since you have written the articles in your blog, you know what information you have in your blog - and letting people search your blog on your terms is more logical. A properly structured label array lets your potential repeat visitors find related articles in your blog. You can see my label array on my Topics page.
An unfortunate limitations of labels is that any labels search can only consider one label at a time.
As an example of how that restricts label usefulness, here are four Topics that are discussed with some volume.
"Cache and Cookies" is a topic that could be expressed, in logical terms, as "Cache" ^ "Cookies" - that is, all posts that discuss cache and cookies together. If Blogger was a properly designed Content Management System, it would be possible to dynamically search for posts which used labels "Cache" and "Cookies" together - that is, a compound label search.
Some - but not all - posts which discuss "cache and cookies" are relevant to "layered security". Since label searches are simple, I had to statically label specific posts as "Cache and Cookies", similar to "Cache", "Cookies", and "Layered Security". A dynamic search of "Cache" ^ "Cookies" (Both "Cache" And "Cookies") - or maybe "Cache" | "Cookies" (Either "Cache" Or "Cookies") - would be very useful to my readers.
If you believe, as I and a few others do, that some ability to compound label searches would vastly expand the usefulness of labels, make your thoughts known to Blogger.