Although it's a bit hard to follow, Dr. Garcia (aka Orion), who operates the Miislita site and blog, has a great blog post on the Latest SEO Incoherences (a clever acronym pun on LSI). He takes issue with SEO/M firms who advertise that they  use LSI or SVD tactics to make their services more competitive and valuable to clients:

Their current stop appears to be LSI and SVD, two scientific acronyms that stand for singular value decomposition and latent semantic indexing. In an attempt to sell whatever they sell, one can see now a crew of search engine marketers reciting these terms in their search marketing conferences, forums, blogs, press releases and any other marketing channel one can think of.

They are all over the place: from US to Russia to India to Mexico, claiming that they sell "LSI-based services" or do "LSI-based website optimization", "LSI-based link building", have patented an "LSI tool", "reversed engineered LSI", yadda, yadda, yadda.

Such "bottles of snake oil" are easy to sell to ignorants, especially when clients still have hard time figuring out what SEO or HTML stand for.

Their pattern -talk about something, explain nothing- is obvious. When not quoting each other hearsays, they paraphrase or copy/paste lines from the LSI literature, speculate about how search engines implement LSI or even come up with their own theories.

Their trail - combine science with marketing lingo- is obvious, too. They will put online any argument that will help them to sell something. Quite convenient, hugh.

Still, you will not find these unscrupulous marketers any time soon providing how-to stepwise calculations explaining how LSI or SVD works.

For those who are interested, Dr. Garcia also has a tutorial that fully explains the myths and examines the IR uses for LSI & SVD. I'm struggling to comprehend it (and will probably seek some help from Si when I have the chance), but Dr. Garcia's point about the limited application of this science towards the marketing or rankings of a website from a search-engine external perspective makes a very clear case.

I see at least a few dozen companies attempting to market in this fashion.