Exchange-traded funds tracking the Internet sector were among the top performers of Thursday's session, thanks to solid first-quarter earnings from RealNetworks ( RNWK). The Internet-software maker posted a profit that beat Thomson First Call's average earnings per share target by a nickel. Recently, RealNetworks was jumping 9.4%. Among other names, Amazon.com ( AMZN), CNET Networks ( CNET), eBay ( EBAY) and Checkfree ( CKFR) were all higher by 1.5% or more. The B2B Internet HOLDRs ( BHH) was climbing 4 cents, or 2%, to $2.07. The Internet HOLDRs ( HHH) was adding 85 cents, or 1.4%, to $60.36. The Internet Infrastructure HOLDRs ( IIH) was gaining 4 cents, or 0.8%, at $5.06. Meanwhile, an earnings beat from Symantec ( SYMC) boosted the Internet Architecture HOLDRs ( IAH) by 39 cents, or 0.9%, to $45.07. Telecom HOLDRs ( TTH) also was higher, thanks to Centurytel ( CTL), which rose more than 4% after beating first-quarter estimates and raising its guidance for the year. The ETF was recently up 45 cents, or 1.2%, to $38.74. On the losing side, bundled securities tracking oil tumbled due to a drop in crude prices. Recently, the front-month June contract was down 83 cents to $62.85 a barrel. Crude oil prices have now fallen more than 5% since Friday's close. The iPath Goldman Sachs Crude Oil Index ( OIL) ETF eased 33 cents, or 0.9%, to $35.99. The United States Oil ( USO) ETF shed 40 cents, or 0.8%, to $49.19. The ProShares DB Oil ( DBO) was losing 11 cents, or 0.4%, at $26.15. The Biotech HOLDRs ( BBH) was also among the worst decliners Thursday. Among its holdings, Biogen-Idec ( BIIB) was losing 2%, Amgen ( AMGN) shed 2% and Shire ( SHPGY) dipped 1%. Recently, the Biotech HOLDRs was lower by $1.58 to $188.84.