Well, a little research in my library of technical books turned up some interesting facts.
As we all know "high" is a relative term.
F'rinstance my 1981 Schwinn-Psonic Le Tour Tourist has a sticker on the bottom of the seat tube claiming "Certified AISI 1020 Tubing".
A little research in my reference books shows C1020 hot rolled steel has a tensile strength of 67,000 PSI while the cold drawn version has a tensile strength of 74,000 PSI.
Now C1020 steel is pretty low in the pantheon of alloy steels which starts at C1008 and runs as far as C12(L)15, all of these alloys having NO chromium or molybdenum in them.
Once you get into C1320 and higher numbers (C2XXX, C3XXX and C4XXX), you are now looking at the true cro-moly steels with increasing tensile strengths compared to the non-cr-mo steels.
So the C1024 tubing mentioned by pirate (in the linked thread above) is not anything special but is somewhat stronger than my C1020 steel.
C1024 steel has a hot rolled strength of ~69,000 PSI ad a cold drawn strength of ~78,000 PSI......so it is somewhat stronger than C1020.
At the end of all this arcania, we can see that "high tensile" is certainly a very relative term and is, IMO, no more than an advertising trick to fool the unknowing consumer.