I hope you don't mind a random reader posting comments...
Blurbs interest me the most when I know that I like what the blurbing author writes. I really love Pamela Dean's writing, for example, so anything she recommended I would be more inclined to check out. If I really /don't/ enjoy the blurbing author it doesn't rule out an interest in the book, but it does make me slightly more dubious.
The content of the blurb also matters - generic adjectives ('fabulous!') are uninformative, and unlikely superlatives (like your 'best thing since Tolkien' example) tend to leave me entirely cold.
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Blurbs interest me the most when I know that I like what the blurbing author writes. I really love Pamela Dean's writing, for example, so anything she recommended I would be more inclined to check out. If I really /don't/ enjoy the blurbing author it doesn't rule out an interest in the book, but it does make me slightly more dubious.
The content of the blurb also matters - generic adjectives ('fabulous!') are uninformative, and unlikely superlatives (like your 'best thing since Tolkien' example) tend to leave me entirely cold.