Search engines look at text labeled as headings very carefully, so make sure your post or page uses these tags in a meaningful way. (webdesignrelief.com)
It is important that each image have a unique caption in the alternative text label, even if the same image is used more than one location in a document. (slaw.ca)
The center stack is covered in capacitive buttons with tiny text labels that are difficult to read at a glance. (cnet.com)