Oligosaccharides as Informational Molecules?

[Matt Sandel]

    Today in Biology class my professor said that polysaccharides are
not ever informational molecules.  However, last year, my high school
biology teacher had mentioned in class that they had discovered that
some cells have Oligosaccharide chains attached to the outside of their
cell membranes and that these have cell identification functions.  My
questions are thus 1) Is this statement regarding Oligosaccharides true?
And 2) If so, does that make these Oligosaccharides informational
molecules?  Thanks.
Matt Sandel