Updated from 7:06 p.m. EDT

After-hours sluggers kept the scorekeepers busy this week, as traders belted out as much as 6.4 million shares on

Instinet

Wednesday night and 5.4 million shares on

Island

ECN Thursday evening. Behind the extra-inning volume rallies was a burst of activity in the optical-networking sector.

As is typically the case on Friday nights, the pace of postclose activity slowed tonight. Nonetheless, optical and networking plays returned to the spotlight.

Shares of

JDS Uniphase

(JDSU)

, tonight's most-active stock on Island ECN, gained 31 cents, or 0.4%, to $77.56 and improved 42 cents, or 0.5%, to $77.67 on Instinet. The optical-component maker increased $2.81, or 3.78%, to $77.25 during the regular session.

Last night, JDS posted earnings that surpassed Wall Street's targets and put forth a bullish forecast on future quarters during a conference call with analysts. JDS Uniphase raised its targets for its second quarter and fiscal 2001, which sent its stock up 11% in Thursday's extended trading session.

JDS Uniphase's gains came on the heels of a major selloff in the technology sector, triggered by a disappointing revenue report from

Nortel Networks

(NT)

on Tuesday night. Indeed, Nortel's announcement sent the

TheStreet Recommends

Nasdaq Composite Index down 190 point Wednesday. JDS, for its part, dropped 25%, while Nortel plunged 28.9% that day.

In twilight action on Instinet, Nortel Networks -- a onetime holdout in the beaten-down tech sector --shed 19 cents, or 0.4%, to $42.38, bringing it down 33.1% since its third-quarter earnings announcement Tuesday.

Networking giant

Cisco Systems

(CSCO) - Get Report

, which has seesawed since Nortel reported on Tuesday, lifted 44 cents, or 0.9%, to $51.13 on Island Instinet tonight. (Cisco dropped 7.74% in sympathy with Nortel on Wednesday.)

In the Net corner,

NBC Internet

(NBCI)

climbed to third place on Island's most-active list, a day after the release of its third-quarter financial results. Thursday, the Internet media company posted a narrower-than-expected loss and said it will reach profitability about two quarters ahead of schedule. Today,

Goldman Sachs

trimmed its loss estimates for the company. At last look, NBCI was up 34 cents, or 6.04%, to $6.03 on Island.

This information is provided by Instinet, a wholly owned subsidiary of Reuters (RTRSY) . For further information, please contact Instinet at www.instinet.com.

Island ECN, owned by Datek Online, offers trading, mainly in Nasdaq-listed stocks, from 7 a.m. to 8 p.m. EDT.

Confused?

TheStreet.com

explains how the rules change when the sun goes down in Investing Basics: Night Owl, a section devoted to after-hours trading.