Signs are emerg­ing that ven­ture cap­i­tal firms are becom­ing less enam­ored with e‑commerce star­tups in the lat­ter part of 2012, espe­cial­ly if they can’t fur­nish hard evi­dence of their growth prospects.

Investors were robust­ly opti­mistic about new e‑commerce enter­pris­es in 2012, right up until Q3, with For­rester Research fore­cast­ing that online sales would surge from $226 bil­lion in 2011 to $327 bil­lion in 2016 (that’s a 45 per­cent increase).  E‑commerce man­agers were smil­ing from ear to ear in the third quar­ter of 2012, as ven­ture fund­ing gal­loped to $242 bil­lion – twice the lev­el it attract­ed in the same quar­ter of 2011.

Are val­u­a­tions too high?

But the mood may be chang­ing, bring­ing new headaches for web con­tent man­agers and e‑commerce ana­lysts.  New York based start­up Fab Inc., a lux­u­ry wares mar­ket­place launched in 2011, is a case in point.  Although it enjoyed a blast of pop­u­lar­i­ty after its inte­gra­tion with Face­book; a move which boost­ed its mem­ber­ship to 9 mil­lion, it appears to be brac­ing itself for a tougher fund­ing climate.

As recent­ly as July, the firm jubi­lant­ly man­aged to raise $105 mil­lion, head­ed by Lon­don based Atom­i­co.  But Fab’s CEO Jason Gold­berg was nonethe­less forced to send a let­ter to exist­ing investors drop­ping Fab’s val­u­a­tion from $700 mil­lion to $600 mil­lion in June, just one month fol­low­ing Facebook’s IPO. Even after that some investors were reluc­tant to get involved, con­sid­er­ing even $600 mil­lion to be an overestimate.

A sign of the times or mis­tak­en perception?

Sequoia Cap­i­tal part­ner Alfred Lin makes no secret of the fact that he’s kept e‑commerce at arm’s length since join­ing his cur­rent firm in 2010.  In a some­what omi­nous com­ment, he said, “We cer­tain­ly have dis­cussed e‑commerce in part­ner meet­ings.  We’ve got­ten to the point where we were doing due dili­gence and were inter­est­ed in invest­ing, but val­u­a­tions have tak­en over at lev­els that we think are not sustainable.”

Bri­an O’Mal­ley, gen­er­al part­ner at Bat­tery Ven­tures, shares Lin’s views.  Although his firm has recent­ly sunk fund­ing into e‑commerce star­tups like home fur­nish­ings ven­dor Ser­e­na & Lily, flower-deliv­ery sub­scrip­tions ser­vice H. Bloom and men’s cloth­ier J. Hilburn, O’Malley is resist­ing fur­ther e‑commerce invest­ments because the val­u­a­tions seem improb­a­bly high.

The future, it seems, lies in up-and-com­ing e‑commerce firms refrain­ing in the most dis­ci­plined way from irra­tional val­u­a­tions and keep­ing their eco­nom­ic heads on straight.