Labels Searches, And Case Sensitivity

We see confusion, from time to time, about label searches in Blogger Help Forum: Get Help with an Issue.
Why don't my labels work, consistently?
Why don't all of my pages work?
Looking at a blog with the problem, we'll frequently see lack of consistency in label case - some labels appear in lower case ("label"), some in upper case ("LABEL"), some in sentence case ("Label"). This might seem like an insignificant personality issue - but it's not.

Label searches are case sensitive - that is, upper case letters are different from lower case letters.

People who do not write natively, in languages which use the "Latin" alphabet (is that the correct term?) are not always attentive to case variations. We observe this frequently, with people who DO NOT UNDERSTAND THE PROBLEM WITH SHOUTING, in forum discussions.

In a label search, "Case Sensitivity" and "case sensitivity" will produce different results. Click on the two links, and check out the different results.

If you are going to use labels effectively, in your blog posts, you must be scrupulously consistent with use of mixed case.

Choose your preference when using lower / upper case characters.

Some people use all lower case letters, some UPPER CASE, others use Sentence Case, in their labels. I feel that the latter makes my posts easier to read, so that is how my labels are entered. I do the same, with my posts, and the sentences.

To illustrate the problem, I tried to labeled this post with both "Case Sensitivity", and "case sensitivity" - but was blocked, by Blogger. You can click on the example links - but one will yield no results.

Be aware of "case preservation" vs "case sensitivity".

Case sensitivity is a subject of some controversy. Some people confuse the issues of "case preservation" and "case sensitivity".

There are two competing conventions, used by the two competing server operating systems, "Linux / Unix" and "Windows" - and comparisons between the two sometimes involve discussion about "case preservation" vs "case sensitivity".

The latter issue becomes important, because both Unix and Windows servers are used in DNS and other Internet infrastructure applications. This includes applications which will resolve "" and "", as different addresses.

This issue has been explored previously, as a problem with custom domain publishing - and before that, with "FTP" Publishing.

The difference between "case preservation" and "case sensitivity" has history.

When Blogger Engineering developed labels for Blogger blogs, and added various gadgets like "Labels" (aka the "Labels Index"), they did not decide to make "Case Sensitivity", and "case sensitivity", differently unique, on a whim. It took several months, before they got all of the issues straight.

And even now, we have people who can't get their label searches correct, and try to index "Case Sensitivity" with some labels entered as "case sensitivity".

Make your own choice - and be consistent in your choice.

When you setup labels, in your blog, decide on a convention - then stick to your convention, consistently. Or, deal with the problems, periodically.

All #Blogger blog owners do not instinctively understand the "Latin" alphabet, and its conventional mix of lower and upper case characters.

Inconsistent use of mixed case can be a problem, with various Blogger blog features. Using labels is one example of this problem.


Hello there.
This post has come at just the right time for me. I've been having issues with my labels for a week now and couldn't find a solution to the problem...some of my labels produced results while other produced just a blank page like in your test. I had no idea of the sensitivity issue. I just thought my blog had been infected so back I will go and redo my labels. Thank you for the information.