Strange messages in Usenet

I have notice that sometimes some newsgroups will get spammed with some useless nonsense messages like the example I paste below:

"She should challenge the cautious victory and weep it into its
beach. He should mostly straighten regarding successful convincing
careers. When Ramez's effective potential taxs, Norbert summons
on the part of natural, historic obstacles. She wants to invoke
select accusations up to Mustapha's reception"

Usually it will not be only one it will be many of then in series and they appear in various newsgroups, they do not seem ot advertise anything or provide any link to any website, does anybody know what is this?