In addition to hearing professional news announcers use singular verbs with plural nouns (There’s thousands of reasons to do this…), which makes me very grumpy, I often see symbols like @ and & used in running text. This is offensive to the seasoned typographer. Don’t do it!
Remember the overarching theme of these essays: Never interrupt the reader!
This is an exaggerated example of the use of @ and & in running text. If you squint, you’ll see the blobs. These, in addition to being visually unpleasant, cause the reader to stop, translate, and then continue. It’s typographically unwise.
In general, the ampersand and the at-symbol are used to abbreviate things when space is tight. In running text – books and similar typography – one should not abbreviate any word. The words “and” and “at” should be spelled-out. This is also true of abbreviations for states – CA, MO, AZ, etc. These should always be spelled-out, except when used as an address. California is a beautiful word; CA is an ugly postal code. Don’t use the postal code in text.
These characters – @ & and abbreviations like CA, create visual blobs. Blobs interrupt reading because the reader has to stop and interpret them, converting them back to words. This takes time and it interrupts the reader. That violates our objective of never interrupting the reader.
…and this is the same text (from Les Miserables) with the words at and and used correctly. It reads smoothly.
And excellent typography does not interrupt the reader.