To be alerted on an exact phrase, be sure to put it in quotes. Also use quotes around a word to avoid stemming (where ‘horse’ would also match ‘horses’).
You should only enter one term per alert – if you wish to receive alerts on more than one thing, or for more than one person, simply fill in this form as many times as you need, or use boolean OR.
For example, if you wish to receive alerts whenever the words horse or pony are mentioned in Parliament, please fill in this form once with the word horse and then again with the word pony (or you can put horse OR pony with the OR in capitals). Do not put horse, pony as that will only sign you up for alerts where both horse and pony are mentioned.
The mySociety blog has a number of posts on signing up for and managing alerts: