[lloydde]

It’s not a small niche. Search any job board and ETL will show up in a large presentage of job posts and resumes related to software QA and data validations.

[spc476]

HTML does have the <ABBR> tag. How hard is it to do?

    <abbr title="Extract, Transform, Load">ETL</abbr>

Even once?

[lloydde]

I was not disagreeing with the recommendation. It’s almost always a good idea to spell out an acronym/initialization on first use.