The site's key search term is a profession, and you can have it as -er, -ers or -ing.
The -er and -ers version occur a fair bit on the home page, so I thought I'd be clever, 'under-optimise', and use -ing for the title tag. A category in the blog has a title tag with -er.
After some work on some OK links (75% anchors on the brand / url, 25% on other anchors, all very random) we've hit page one for all three versions of the term, BUT
- the blog page ranks for -er and -ers,
- and the home page only for -ing (the least popular term)
Ranking position is same the across all three terms.
The home page does appear for the -ers version of the term but down on page 7!
The blog page has no external links.
I'm pretty sure that this isn't a penalty.
I know that tweaking by itself can get you demoted in the short term, but you should come back even if you just touch the title tag.
I plan to risk the tweak, but also add a load of new content to the home page to support this (we're expanding the focus, similar to getting the page to target 'estate agent' as well as 'letting agent').
I would welcome input/advice/experiences.